Working memory is a core executive function supporting dual-task locomotor performance across childhood and adolescence.

Most daily-life ambulatory tasks involve dual tasking, for example, talking while walking. In children, the evidence supporting the effects of age on dual tasking is confounded by the difficulty of the cognitive task and lack of adjustment to suit individual cognitive abilities. To address this issue, the current study examined the effects of age, cognitive load, and executive functioning on the degree of dual-task gait interference across childhood and adolescence. We tested 120 typically developing children aged 6-11 years, adolescents aged 12-16 years, and young adults aged 18-25 years. Participants were asked to walk while performing a visuospatial working memory task at two levels of cognitive load (easy and difficult) adjusted to suit each participant's cognitive ability. Spatiotemporal characteristics and intra-individual variability of gait were measured using a GAITRite electronic walkway. Irrespective of the cognitive load level, children aged 6 to 11 years showed greater dual-task gait interference for selective spatiotemporal gait characteristics; however, the younger children showed a trade-off pattern in gait variability whereby they prioritized gait stability at the expense of cognitive performance. Our results also showed that age and working memory capacity were significant predictors of dual-task interference for a range of complementary gait parameters in the combined sample. Importantly, working memory capacity was part of a moderating relationship between age and dual-task gait interference. These findings emphasize the importance of dual-task prioritization strategies in younger children and highlight the role of individual differences in working memory capacity in performance in dual-task gait situations.